-f is used to specify the Watchfile which contained watch rules. default is "./Watchfile"
-i special the minimum recompile interval.Default is 500ms.

When change between minimum interval,the compile process will not be abort,and the latest change will not compiled.In order to prevent unwanted result the -i should be less than default settings.

When change happend after minimum compile interval,then an recompile will triggered,by your rules defined in Watchfile(latter example).But when the last change-compile is still running,That one will be aborted.

#Watchfile

#create an default Watchfile at ./

watchcompile -c

A default Watchfile is like below

//{basename} /css/style.less => style.less

//{fullpath} /css/style.less => /css/style.less (unchanged)

//{filename} /css/style.less => style

//{extname} /css/style.less => .less

//{directory} /css/style.less => /css/

exports.watchList =[

[/^.*coffee$/,"coffee -c {fullpath}"]

,[/^.*less$/,"lessc {fullpath} > {directory}{basename}.css"]

]

Watchfile is considered as an standard node module and latter running by require("vm").runInContext.
exports.watchList MUST be an Array of 2 dimension.Each of the elements contain [RegExp for matched file,cmdline for what to do when compile]